Proteins That Promote Filopodia Stability, but Not Number, Lead to More Axonal-Dendritic Contacts

Dendritic filopodia are dynamic protrusions that are thought to play an active role in synaptogenesis and serve as precursors to spine synapses. However, this hypothesis is largely based on a temporal correlation between filopodia formation and synaptogenesis. We investigated the role of filopodia in synapse formation by contrasting the roles of molecules that affect filopodia elaboration and motility, versus those that impact synapse induction and maturation. We used a filopodia inducing motif that is found in GAP-43, as a molecular tool, and found this palmitoylated motif enhanced filopodia number and motility, but reduced the probability of forming a stable axon-dendrite contact. Conversely, expression of neuroligin-1 (NLG-1), a synapse inducing cell adhesion molecule, resulted in a decrease in filopodia motility, but an increase in the number of stable axonal contacts. Moreover, RNAi knockdown of NLG-1 reduced the number of presynaptic contacts formed. Postsynaptic scaffolding proteins such as Shank1b, a protein that induces the maturation of spine synapses, increased the rate at which filopodia transformed into spines by stabilization of the initial contact with axons. Taken together, these results suggest that increased filopodia stability and not density, may be the rate-limiting step for synapse formation

Purification of molybdenum oxide, growth and characterization of medium size zinc molybdate crystals for the LUMINEU program

The LUMINEU program aims at performing a pilot experiment on neutrinoless double beta decay of 100Mo using radiopure ZnMoO4 crystals operated as scintillating bolometers. Growth of high quality radiopure crystals is a complex task, since there are no commercially available molybdenum compounds with the required levels of purity and radioactive contamination. This paper discusses approaches to purify molybdenum and synthesize compound for high quality radiopure ZnMoO4 crystal growth. A combination of a double sublimation (with addition of zinc molybdate) with subsequent recrystallization in aqueous solutions (using zinc molybdate as a collector) was used. Zinc molybdate crystals up to 1.5 kg were grown by the low-thermal-gradient Czochralski technique, their optical, luminescent, diamagnetic, thermal and bolometric properties were tested.Comment: Contribution to Proc. of Int. Workshop on Radiopure Scintillators RPSCINT 2013, 17-20 September 2013, Kyiv, Ukraine; to be published in EPJ Web of Conferences; expected to be online in January 2014; 6 pages, 6 figures, and 3 table

Taking the Heat out of the Burning-ice Debate: Potential and Future of Gas Hydrates

AbstractFinding gas hydrates to be a controversial, polarizing subject, the SBC Energy Institute (SBC-EI) developed a fact-based report, presenting: the key concepts; the status of exploration and production technologies; the status of research, development and demonstration (R,D&amp;D); and the environmental and safety challenges associated with the potential exploitation of this resource. In addition to leveraging the long involvement of Schlumberger in gas hydrates R,D&amp;D, the SBC-EI performed a literature review and engaged experts in the gas-hydrate field. The SBC-EI also analyzed patents from 50 offices worldwide, using the Thomson Derwent World Patents Index, and conducted a survey of gas-hydrate stakeholders to present the state of R,D&amp;D and a faithful picture of current thinking among academics and industry players involved in the field. Among various types of deposits, gas hydrates hosted in sand-dominated sediments both within permafrost and offshore stand out as the only resources that may be recovered in the near term. Contrary to common belief, these deposits can largely be identified using existing exploration technologies, with small adjustments. Stakeholders widely agree that depressurization is the best technology for producing gas hydrates from sand reservoirs, whereas interest in CO2-CH4-exchange production techniques have lost momentum. Nevertheless, gas-hydrate exploration and production raise significant technical challenges that, unresolved, could undermine the resource's commercial viability. R,D&amp;D remains a vital part of assessing the potential and economic viability of gas hydrates, and of addressing environmental and safety concerns. It is unlikely that gas hydrates will become competitive in gas-rich areas. But there is a much stronger possibility of commercial development in energy-deficient regions such as Asia, where gas-hydrate projects could alleviate energy-security concerns and strenghten energy independence. This would have revolutionary consequences for the energy sector. However, before this is possible, long-duration production tests are required. Japan is leading the way in this area and is aiming to achieve commercial operation by the end of the decade. This paper provides a fact-based review of existing knowledge on gas hydrates as a potential energy source. It is supported by two innovative analyses: (i) a comprehensive survey of gas-hydrate experts; and (ii) an in-depth examination of worldwide patents of gas-hydrate technologies.</jats:p

La pollution soufrée limite-t-elle le développement de la maladie de l'écorce du hêtre ? (Cryptococcus fagi, Nectria coccinea)

International audienc

La pollution soufrée limite-t-elle le développement de la maladie de l'écorce du hêtre ? (Cryptococcus fagi, Nectria coccinea)

Des comptages d’arbres malades en zone plus ou moins polluée et en zone témoin montrent que la maladie de l’écorce du hêtre se développe d’autant moins que la pollution est plus forte. Le développement des deux agents de la maladie est perturbé. Le Nectria est nettement freiné. La répartition des pullulations de Cryptococcus est modifiée de façon plus complexe. Différentes hypothèses sont suggérées pour expliquer ces faits. Leur vérification nécessite de nouvelles recherches.Observations of affected trees in more or less severely polluted areas and in a non-polluted control area have shown that the development of Beech barkdisease decreases with increasing pollution levels. The development of both disease agents is modified. Nectria development is clearly slowed down. The distribution of Cryptococcus outbreak is modified in a more complex manner. Several hypotheses are suggested to explain these observations ; further research is necessary for their confirmation